Device for the disruption of explosive ordnance

ABSTRACT

A plurality of embodiments of disruptor all have a container with an enclosure for explosive material with a wall which can he located in any one of a number of different positions using one or more tubular spacers ( 12 ) optionally of various sizes thereby to provide a wide range of capacity of enclosure and hence explosive material.

The present invention relates to a device for the disruption of a widerange of types of explosive ordnance.

It is frequently required to disassemble items of conventional explosiveordnance and of improvised explosive devices such as may be fabricatedby terrorists and criminals, in order to render them safe. Unless asuitable method of disassembly is carefully applied, any interventionmay cause the target to explode. One traditional method consists ofmanual separation of components in such a way that the initiatingmechanism is rendered unable to operate. By means of remotely controlledmanipulators, this disassembly may be carried out at a safe distance inorder to protect the operator from injury were the target device toexplode or ignite during the intervention.

Another commonly used method consists of the very sudden disruption ofthe target device using a charge of high explosive. This method dependsupon the separation or breaking of components of the initiationmechanism, or the separation of the initiation system from the mainexplosive or pyrotechnic charge, before the device has time to function.

This method is most easily applicable to mechanically weak, improvisedexplosive devices (IEDs).

Alternatively, when rendering safe a more robust conventional munitionbelieved not to have a sensitive fusing system, (such as an air-dropped,steel-cased bomb), the shock generated by the explosive method may beused to cause the explosive fill to be ignited without detonation.Confinement of the copious gas produced by the decomposing explosiveusually results in a non-detonative “low order” explosion which burststhe case open and scatters any remaining explosive.

Such explosive methods may consist of a simple “donor” charge of highexplosive, such as plastic explosive or a block of trinitrotoluene,placed close to, or in contact with, the target device. A greatdisadvantage of this type of attack is that it yields unpredictableresults, and unwanted detonation of the target munition frequentlyoccurs.

Explosive may alternatively be used as the source of power in a tool forthe disruption of explosive targets; such a tool is commonly known as a“disruptor”. In this case, the explosive used is usually anon-detonative propellant rather than high explosive and it is used topropel a disruptive projectile from a gun barrel; it may alternativelybe high explosive used as a component of a “shaped charge”.

In the latter case, which is usually but not exclusively used againstconventional munitions, (usually encased in such hard materials as steelor aluminium alloy), one end of a small explosive shaped charge isprovided with a metal-lined, radially symmetrical, cavity. This metallicliner is collapsed by the progressive detonation wave front so as togenerate an extremely fast-moving jet of metal. This penetrates the caseand injects hot metal into the explosive or pyrotechnic fill, causing itto ignite or to explode. Such charges are usually employed at“stand-off” distances corresponding to four or five charge diameters. Ina variant of such disrupting charges, the use of a cavity liner providedwith only shallow concavity yields a projectile consisting of a coherentmass, or “slug”, of hot metal which can be projected over relativelygreat distances, typically equivalent to tens or hundreds of chargediameters. The impact of such projectiles frequently causes the targetmunition to detonate as a result of the shock wave generated, and issometimes intended to induce such detonation but, if the hot injectedmaterial causes the fill to ignite rather than to detonate, the internalpressure generated by the gaseous combustion products usually causes thecase to burst violently, albeit without detonation. Such violentdisruption often causes the burning residual explosive to beextinguished but the method always carries the risk of unwanteddetonation.

A further method in which high explosive is used for attackingconventional munitions is the use of sheet explosive for the projectionof a flat plate in order either to make a hole of large diameter in atarget munition or, alternatively, to knock off the external nose fuseof a shell or bomb.

Disruptors consisting of a robust, smooth-bore, gun barrel employ ablank propellant cartridge to project an inert mass at the targetmunition. This mass may consist of metal shot, a steel slug, orparticulate metal in a plastic, viscous aqueous or plaster matrix. Sucha method is most commonly used to project water at relativelythin-skinned improvised targets in order to burst them open or to removethe end-cap from a pipe bomb. One particular variant is the use of arifle, usually of large calibre, such as 0.5 inch, to strike themunition from an armoured vehicle at a safe distance. Such weapons areused for the disruption of mines, sub-munitions, explosive projectilesand steel-cased aircraft bombs. One of my earlier inventions, describedin British Patent Specification GB2292445, consists of a disrupter whichcombines the advantages of high explosive as a propellant with water asa projectile and which projects water at much higher velocities than areordinarily attainable using a gun barrel using shaped chargeconfigurations in which the cavity in the explosive charge is lined, oris filled, with water or other liquid or liquescent material.

In order to be prepared to carry out successful render-safe procedures(RSPs) on the multiplicity of possible types of target devices chargedwith explosive or pyrotechnic composition which he may encounter, theexplosive ordnance disposal (EOD) operator presently needs acorresponding multiplicity of tools. These, typically, include malleableplastic explosive, sheet explosive, detonators, two or three types ofmetal shaped charge case, a gun for projecting water, and another forprojecting steel slugs or chisels, as well as factory-filled cartridgesand, in some cases, shaped charges.

Existing devices in which high explosive is used as the propellant arealmost invariably used in conjunction with a metal projectile, such as acopper or iron cone, dish or plate. The body is usually made of steel oraluminium. According to national practice, the device may be issued tothe user pre-filled with explosives in a factory or it may be issueduncharged, and the filled extemporaneously by the user using plastic or,occasionally, liquid explosive.

Most such devices are derived from the technology developed for use asshaped charge warheads in armour-piercing missiles and the user has nocontrol over their performance other than choosing the point of aim andthe stand-off distance.

In the case of one such pre-filled device, the manufacturer provides aseries of brass discs which the operator can place between the disrupterand the target in order to mitigate the violence of impact of the jet ofmetal which it generates on the target munition. Such disruptors arecommonly referred to as “weapons” and suffer the disadvantage thatregulations require that they be acquired, transported, stored andissued as explosive items.

In variants of known inventions, in which the body of the disruptor issupplied empty to be loaded by the operator with plastic explosiveimmediately before use, the dished or conical projectile is fixed at oneend by means of a crimp in the extremity of the case or it is a slidingfit within the body and urged against an internal rim at one end by theexplosive which the operator tamps behind it. The means of initiation isusually a detonator and the part supporting it usually consists of adisc or plug with an axial hole. Such arrangements have the advantage ofgiving the operator an additional variable parameter: although theexplosive properties of one military plastic explosive varies but littlefrom another, the amount of explosive used, and hence the energy outputof the device, can be varied by the operator. The limitations even ofthese disruptors are such that they are generally used for only one typeof intervention on a target munition, the so-called “low-order”disruption of shells and bombs in which the case is penetrated by hotmetal which ignites the explosive fill; this burns so vigorously thatthe case cannot stand the copious volume of gaseous combustion productsand bursts violently. This method frequently results in unwanteddetonation (or “high order” reaction).

The high probability that disruptors and donor charges of explosivefired in contact with conventional munitions, such as bombs dropped fromaircraft, will cause unwanted detonation of the target munition isattributable to the large amounts of explosive required for suchoperations according to usual contemporary practice and to the diameterof such charges. A contact charge large enough in diameter and thicknessto perforate reliably the steel case of a typical air-dropped bomb,which may be as much as twenty five millimetres thick, is precariouslyclose to the size sufficient to detonate its fill and such unwanteddetonations occur frequently when they are used.

Not only is the quantity of explosive required often sufficient toinduce such detonation but the diameter of the charge needed to inducereaction of the target munition's contents is frequently excessive. Inorder for detonation to occur throughout a mass of explosive it isnecessary for a high pressure shock wave to run far enough for theexplosive decomposition it induces to become self-sustaining. This isknown as the “run distance” and is a constant for a given explosive. Thedistance that the requisite high pressure shock wave will be maintainedas it passes through an explosive target is a direct function of thediameter of the zone of its surface subjected to explosive attack and,in contemporary EOD practice, this is such that the run distance islikely to be exceeded for the types of explosive most often used forfilling munitions.

Many of the resulting unwanted detonations are then frequently buterroneously attributed to the known process of “burning to detonation”or “deflagration to detonation transition” (DDT), which process consistsof an initially combustive reaction which accelerates exponentiallyunder the condition of confinement until a shock wave is generated whichresults in the detonation of the remaining explosive fill. In fact, manyof these incidents are attributable to direct shock initiation by thedonor charge or to the indirect action of the high velocity, highdensity, and wide-bodied projectile striking its surface.

Those gun barrel disruptors which project water are of two generaltypes: those in which the water is pre-loaded into the same cartridge asthe propellant and those in which the propellant, which is a fastburning powder of the type used in conventional small-arms cartridges,is loaded in a blank cartridge case. The water is then poured into thebarrel where it is retained by a plastics or rubber plug. Suchdisruptors have the disadvantage of powerful recoil and limitedprojectile velocity. Since most are made of steel, they are too heavyfor deployment by small remote-controlled vehicles. The use of materialsof lower density than steel increases the velocity of recoil. Suchrecoil may be reduced by the simultaneous discharge of water or gasrearwards but the advantage of such an arrangement is largely negated bythe extra weight of the additional components required for this purposeand the increased blast and projectile effect behind the disrupter.

A variant of the gun barrel projects a steel slug rather than water.Such a slug may be flat-nosed or it may have one end in the shape of achisel. Such projectiles are sometimes employed to remove end-caps frompipe bombs and nose fuses from such conventional munitions as shells andmortar bombs. They have the significant disadvantage of a potentialrange of hundreds of metres so constitute potentially dangerous missilesif they miss, or bounce off, the intended target. It is one purpose ofthe present invention to make such potentially dangerous proceduresunnecessary by substituting liquid projectile materials or materials oflower density or combustible materials which, if unconstrained, havemuch shorter ranges.

The present invention discloses a disruptor for providing an explosivecharge, the disruptor comprising a container having a projectile andexplosive material, the container comprising: an enclosure for holdingexplosive material, said enclosure having a wall locatable at any one ofa number of positions thereby to define the capacity of said enclosure.

In this way, the present invention allows a disrupter to have any of arange of capacities of explosive material enclosure.

It is important for an explosive material enclosure to be substantiallycompletely filled with explosive material in order for the resultant jetto be accurately and precisely predetermined.

If the enclosure is not completely filled, the presence of pockets ofair and/or air gaps in the explosive material disrupts the radialsymmetry of the detonation wave front and in so doing prevents thesymmetrical deformation of the projectile and causes it to deviate fromits axial trajectory.

Also the present invention allows a disruptor to be provided with apredetermined amount of explosive material, in that a disrupter can beprepared with a predetermined size of explosive material enclosure, andthen the enclosure can be merely filled with explosive material untilfull, in the knowledge that a specific size of explosive charge is thenavailable.

Preferably, the container comprises one or more spacer elements to holdthe wall in one position and so define the enclosure, and accordinglyalso its capacity. A spacer element may be of annular form, or it may bea block or it may be or some other appropriate shape. A function of aspacer element function is to transmit the longitudinal force from theconsolidating ring to the projectile in order to urge it against theexplosive. It is not a solid shape of such density as would prevent thedeformation of the projectile. Thus typically it is tubular or it couldbe a solid (eg cylindrical) block of such collapsible material as asolid plastic or metal foam. It is possible to have a spacer ring whichis integral with a projectile. A spacer element may form part or all ofthe projectile; for example it may be a solid body (eg of plasticmaterial or of magnesium, or of zirconium or of titanium) or it may havea hollow cavity available for subsequent filling (eg with water or otherfiller) just prior to use.

One or more spacer elements may be located within the container butoutside the enclosure, and/or one or more of the spacer elements may belocated within the container and in the enclosure. The spacer elementsmay be all of the same size and/or they may be of more than one size,thereby to provide overall variety of sizes of enclosure.

In this way, a disrupter can be provided with any of a large range ofsizes of explosive material enclosures from a kit of a few componentparts comprising a single size of container parts and a few spacerelements.

The container of the disrupter may be formed of two parts which are heldtogether by any convenient interengagement, for example a screw-threadfitting, or a groove/recess fitting or interference fit by longitudinalsplines or push-fit arrangement.

The wall of the enclosure may be associated with and/or form part of theprojectile of the disrupter.

A disruptor may have a projectile of any one or more of the followingforms:

(i) a cone;

(ii) a flat disc;

(iii) a wedge of V-shaped cross-section;

(iv) a hollow body for filling by material (eg water) prior to use.

The present invention provides a method of filling a disruptorcomprising a container having a projectile and an enclosure for holdingexplosive material, the method comprising measuring out a quantity ofexplosive material, placing the quantity of explosive material in theenclosure, locating a wall of the enclosure so that the enclosure isfilled with explosive material.

Preferably the method includes providing one or more spacer elements tohold the wall in one position and so define the enclosure.

The method may include measuring out a quantity by weight or by volume.

The present invention also provides a method of filling a disruptorcomprising a container having a projectile and an enclosure for holdingexplosive material, the method comprising locating a wall of theenclosure at one position and placing explosive material in theenclosure until the enclosure is filled.

Preferably the method includes providing one or more spacer elements tohold the wall in one position and so define the enclosure.

Thus present invention may provide a disruptor comprising at least oneor more of the following:

-   -   container with means to vary the capacity of explosive material        held within the container; and    -   means to effect a ready connection between the disrupter body,        and/or explosive material and/or projectile means.

In this way, the disruptor can be readily assembled from a kit of partssuch as to have a particular specified function.

Also, it is possible to provide a disruptor with any of a wide varietyof different criteria by assembling together whichever of a number ofdifferent elements are appropriate. Thus, using a limited number ofbasic elements, a very wide range of disruptors can be quickly andeasily constructed and provided.

The disruptor may have any one of the following features:

-   -   An enclosure with a wall positionable at any one of a number of        locations to define the capacity of the container;    -   A spacer to define the position(s) of the wall of the enclosure;    -   The container and a layer of lacquer or similar moldable or        fixable material;    -   Engagement means on the disruptor and/or the container and/or        projectile means to effect ready connection there between;    -   Screw-thread means on the disrupter and/or the container and/or        projectile means to effect ready connection there between;    -   Push-fit means on the disrupter and/or the container and/or the        projectile means to effect ready connection therebetween.

The present invention also provides a kit of parts for the assembly of adisrupter including any one or more of the elements of a disruptor asdefined in the present invention.

The present invention provides a means of disrupting and rendering safea wide range of types of explosive or pyrotechnic munition or improvisedexplosive device.

The present invention comprises a container which is loaded by the userwith a variable quantity of plastic explosive and a projectile. Bothquantity of explosive and type of projectile are determined according tothe nature of the target to be disrupted and according to the effectwhich it is required to produce thereupon.

One purpose of the invention is to provide the advantage of being inertand free from restrictions associated with the acquisition,transportation, storage and issuing of explosive devices until it isloaded with explosive by the user.

A further purpose of the present invention is to overcome thedifficulties and expense inherent in using gun technology to projectwater, and to project water at much higher velocities than areordinarily achievable with guns. This is made possible by the use oflight plastics materials for construction of the case and high explosiveas the propellant, thus avoiding the necessity of a robust barrel, andthe use of shaped charge technology for imparting directionality to theprojected water.

Since the invention uses cases which are advantageously, but notnecessarily, formed from plastics materials, and employs high explosiveas the propellant, the case disintegrates upon actuation. This meansthat energy is dissipated by the projection of small plastics fragments,and by the generation of a shock wave in the surrounding medium. Thus,no significant recoil is exerted upon its supporting structure. Thisrenders possible its support and deployment by much smaller means thanare required for conventional disruptors of comparable disruptivecapability.

The energy imparted to the projectile material by a charge of highexplosive is a function of the pressure generated by the detonation andof the duration of the high pressure. One optional feature of thepresent invention is a water-filled jacket which, by virtue of its highdensity compared with that of air, impedes the dispersion of the gaseousdetonation products and thus prolongs the period during which theexpanding detonation products act upon the projectile material. It willbe understood that the effectiveness of such a jacket may be enhanced byfilling with a material of higher density.

The present invention also incorporates the optional means of conductingdisruptive operations not only in air but also under water. Thisincreases considerably the scope of its applications. This means mayconsist of an elongate nozzle so arranged that all projectile materialissues through an orifice of very small diameter at its apex. It thusmay provide the additional advantage of permitting the striking of avery small target area while affording considerable protection to thesurrounding area. This is of particular advantage when disabling atarget device in which a small explosive charge is intended to dispersea larger quantity of toxic or biologically active material.

In one embodiment, the present invention is intended to strike a targetmunition over as small an area of its surface as possible in order tominimise the probability of shock-initiation of its explosive contents.This embodiment also provides the means of accelerating projectileswithout concavity to such high velocities as are ordinarily associatedwith conventional shaped charges.

In order that the invention may more readily be understood, adescription will now be given, by way of example only, reference beingmade to the accompanying drawings, in which:

FIGS. 1A and 1B are assembled and exploded views of a longitudinalsection of a disruptor of the present invention in which the projectileis propelled by a full charge of explosive.

FIGS. 2A and 2B are assembled and exploded views of a longitudinalsection of another embodiment of disruptor of the present invention inwhich the projectile is propelled by less than a full charge ofexplosive.

FIGS. 3A and 3B are assembled and exploded views of a longitudinalsection of another embodiment of disrupter embodying the presentinvention in which the projectile consists of a cone of plastics andwater.

FIGS. 4A and 4B are assembled and exploded views of a longitudinalsection of another embodiment of disruptor adapted for use under waterby internal seals and application of a radially symmetrical elongatenozzle.

FIG. 4C is a perspective view of the nozzle of FIG. 4A;

FIG. 5 is a longitudinal section of an embodiment of the inventionadapted for trepanning.

FIG. 6 is an angular projectile;

FIG. 7 is a longitudinal section of an embodiment of the inventionadapted for trepanning and provided with a water-filled jacket;

FIG. 8 is an exploded view of the disruptor of FIG. 7;

FIG. 9 is a disrupter of the present invention supported on tri-podlegs;

FIG. 10 is a further embodiment of disruptor embodying the presentinvention.

FIGS. 1 to 10 show various embodiments of disruptor, each of whichincorporates the features of the present invention as claimed.

Referring to FIG. 1 of the drawings, plastics disrupter 1 consists ofcylinder 2 which is provided with an axial tube 3 which serves tosupport the means of initiation which is most commonly a detonator Dwhich is referenced 5. The tube 3 may conveniently be joined to cylinder2 by a conical zone 4. During the process of loading, the detonator Dmay conveniently, and for the sake of safety, be occupied by a dummydetonator which is slightly shorter and slightly greater in diameterthan the detonator which is to replace it.

The loading process consists of tamping a measured amount of plasticexplosive into the cavity 6 within disruptor 1, extending from the endof the dummy detonator to the rear wall W of the projectile 7. When themaximum amount of explosive is used, the forward edge of the projectile7 is in the same plane as, or a few millimetres proud of, the edge ofdisruptor 1. In this case the projectile 7 may be held inside the cavity6 and urged against the explosive contained therein by the threadedconsolidating ring 8 which engages with the externally threaded portion9 of disrupter 1. The act of screwing the consolidating ring 8 ontodisruptor 1 also ensures that the projectile 7 is axially aligned, asits edge abuts against the integral circumferential ridge 10 within thering 8.

Thus disruptor 1 comprises a container formed of cylinder 2 andconsolidating ring 8 and an explosive materials enclosure defined bycavity 6 and rear wall W of projectile 7, the enclosure completelyfilled with plastic explosive.

Referring to FIG. 2 of the drawings, a projectile 7′ is shown inconjunction with a reduced explosive load 11. In this case, since theinternal ridge 10 of the consolidating ring 8 cannot bear upon the edgeof the projectile 7′, a tubular spacer ring 12 is inserted in thecylindrical part 2 of the disrupter so that one end abuts upon the edgeof the projectile 7′. The internal ridge 10 of the consolidating ring 8then bears upon the other end of the spacer ring 12 so that screwing thering 8 onto the body 1 urges the projectile 7′ against the explosive 11,to be initiated by the detonator 13, ensuring the axial alignment of theprojectile 7′ in so doing.

The disruptor shown in FIG. 2 is essentially similar to that in FIG. 1,with the addition of spacer ring 12 which reduces the size of theenclosure and hence the explosive load 11 in the disrupter.

Filling of the explosive materials enclosure may be achieved in eitherof two ways.

In the first way, the explosive is measured by weight or by volume andthen inserted into the explosive material enclosure in the body whereinit is first compressed, most usually by manual tamping, and then furthercompressed by the consolidating ring which acts either directly, orthrough the intermediary of one or more spacer rings (of a single sizeor of a variety of sizes) as required, on the forward surface of theprojectile.

Alternatively, in another filling operation, the amount of explosive inthe charge is determined by filling of the explosive material enclosurewith such material by loading a slight excess of explosive into the bodyinitially. After insertion of the projectile, the consolidating ring isused to exert longitudinal thrust either directly, or through theintermediary of one or more spacer rings, onto the forward surface ofthe projectile. The body, being provided with a preferably radiallysymmetric array of holes, allows any excess of explosive to be extrudedthrough the holes until the consolidating ring, and any spacer rings,have advanced to a predetermined point. This point is constituted by anend-stop. Such an end-stop may s consist of a shoulder or ridge on theinside surface of the cylindrical part of the body.

Referring to FIG. 3, a conical cavity is formed in the explosive charge21 and the space in front of the cavity filled with water 22. If theexplosive is not sufficiently resistant to contact with water, theinterface may be consolidated by the application of a layer of lacquerto the exposed surface of the explosive or by the interposition of athin plastics cone. The forward front of the water is defined by theinsertion of a plastics cone 23, most conveniently made frompolyethylene for the sake of its easy compliance, into the mouth ofdisruptor 24. This cone, being provided with an integral tubular spigot25 which is tight-fitting, also acts as a stopper and contains thewater. The assembly thus constitutes a shaped charge of generallycommonplace form but with the projectile consisting of a cone not ofmetal but of a polyethylene and water composite. Though lesspenetrating, for a given mass of explosive, than a conventional shapedcharge with a metal liner, the jet formed is still capable ofpenetrating even thick-skinned conventional munitions such as aircraftbombs and possesses considerable disruptive power. It is, however, verymuch less likely to induce deflagration or detonation of the explosiveor pyrotechnic fill of the target munition so it constitutes aneffective tool for the bursting open of small munitions, such asgrenades and sub-munitions, with ejection of the fuses, in cases inwhich minimal violence or recovery and exploitation of components is animportant consideration.

In this embodiment, spigot 25, cone 23 and the cavity filled with watertogether constitute the space-determining element such that the wall ofthe cavity defines the enclosure for the explosive charge 21 and hencethe capacity of the explosive charge.

Referring now to FIG. 4 of the drawings, disruptor 30 is shown with alight explosive load 31 and adapted for use under water as well as inair. Since a small volume of explosive means that the projectile needsto be urged a greater distance down the inside of disrupter 30, a singlespacer would not suffice to transmit thrust from the consolidating ring33 to the projectile 34. In this case, two or more spacer rings 35 maybe employed so that the thrust is exerted through the linear array ofspacers. The use of more than one spacer (optionally of different sizes)can also be employed in other embodiments. In order to prevent theingress of water via the thread 36 locating the consolidating ring 33and disrupter 30, a flat rubber washer 32 is placed at the forward edgeof the outermost spacer ring 35 and an O-ring 37 is located in anexternal circumferential groove in the most forward spacer ring 35.

An elongate cone or nozzle 38 fits on the forward end of theconsolidating ring 33. An O-ring 39 fitted into a circumferentialshoulder on the forward edge of the ring 33 provides a hermetic sealbetween the ring 33 and the nozzle 38. Since the apex of the nozzle 38is closed by a thin, integral, diaphragm 40, the interior of the entireassembly is protected against the ingress of fluids so may be used underwater.

If a projectile in the form of a disc 34 is propelled by an explosivecharge contained within a case such as a disruptor of the presentinvention, the disc tends to disintegrate since each increment of thedisc is propelled by the advancing detonation wave front along anotional line from the tip of the detonator through the centre of thatincrement and the fragments thus produced form a divergent pattern.

An important property of the nozzle 38 is that each of the fragmentsproduced by this mechanism strikes the inner surface of the nozzle 38 ata very acute angle and, in consequence, does not perforate the wall ofthe nozzle 38 but is deflected along the inner surface of its lumentowards the apex. The projected material strikes the end diaphragm 40almost normally so bursts through it and emerges as a projectile of veryhigh velocity.

Since the wall of the nozzle 38 usually remains intact, the surface of atarget attacked by this highly collimated projectile suffers no damageoutside the impact zone.

This embodiment of the invention thus constitutes a means of striking atarget with great precision and great selectivity. This is of particularvalue in the rendering safe of a munition which can be made incapable ofexplosion by the destruction of a specific component with minimal riskof dispersing ancillary components, such as toxic or radioactivesubstances forming part of, or adjacent to, the target munition. Thenozzle 38 also provides a valuable aid to precise aiming in conditionsof low light, as when diving in dark, dirty, water, or in conditions ofdifficult access, as in the case of a small target in an encumberedposition on a floor where line of sight may not be possible. In suchcases it suffices to place the tip of the nozzle 38 in contact with, orclose to, the point of intended impact and to adjust the position of therear of the assembly in order to determine the angle of attack.

It should be noted that this collimating property of an elongate nozzleis not limited to a flat projectile: it may advantageously be used inconjunction with concave or even slightly convex projectiles and may beconsidered as a novel type of shaped charge.

It is known in the art that a conventional shaped charge with a conicalliner produces an elongate “jet” of metal of which the tip, whichderives from the region of the cone near the apex, travels faster thatthe rear-most part of the jet, which derives from the peripheral region,as a result of the higher explosive to liner ratio. Thus, a velocitygradient exists along the jet from the tip to the rear. This causes thejet to increase in length as it moves until it breaks up into a seriesof small pieces travelling at different velocities and in slightlydifferent directions. This phenomenon severely limits the range at whichsuch a jet is effective and means that the optimal stand-off distancebetween charge and target is of the order of five charge diameters.

Since the projectile leaving the nozzle 38 emerges from a hole at theapex of the nozzle which has a cross sectional area much less than thatof the originating projectile 34, it follows that the projectile must behighly elongate. The mode of its formation is very different from thatof a conventional shaped charge and results from the squeezing of a discwhose increments are accelerated at approximately the same rate. Thusthe velocity gradient characterising a conventional shaped charge jetdoes not occur and the rod-like projectile generated by means of thenozzle remains coherent to a greater degree. This implies the potentialfor attacking targets at much greater range than is possible withconventional shaped charges. The nozzle 38 may accordingly beadvantageously be provided with a rear-sight 42 and detachablefore-sight 43.

As with conventional shaped charge disruptors, the invention may useconical projectiles of copper. The relatively high density of copper andits ductility make it suitable material for the generation of highlypenetrating jets but such jets are powerful initiators of detonation. Itfollows that such an assembly constitutes an effective means ofdestroying target munitions by bringing about their detonation,especially if the point of aim is the booster which necessarily consistsof an explosive, such as tetryl or RDX and wax, which is more easilydetonated than is the explosive employed for the main charge, which istypically TNT, a mixture of RDX and TNT or a plastic bonded explosive.

If it is the intention of the operator to avoid detonation but rather tocause the ignition of the explosive or pyrotechnic fill, then the copperprojectile may advantageously be replaced by one of magnesium. Not onlydoes this metal possess a much lower density, which makes it a poorinitiator of detonation, but its low melting point and its affinity foroxygen cause the collapsing cone to ignite. Thus the target projectileis penetrated and injected with exceedingly hot burning metal. Thisconstitutes a powerful means of igniting the composition of the targetmunition.

An alternative for this purpose to a cone of such readily combustiblemetal as magnesium, which depends upon ambient oxygen for itscombustion, consists of a projectile composed of a mixture of twometals, such as aluminium and nickel, or aluminium and palladium, whichreact exothermically if raised to the temperature at which the aluminiummelts. This reaction, in which the two metals form an alloy, does notinvolve oxidation of either components so is independent of ambientoxygen.

Other possible materials for use as projectiles include zirconium andtitanium.

It will be understood that any of the assemblies defined by theinvention may be filled with explosive and assembled by the userextemporaneously but that the invention also lends itself to filling ina factory and provision to the user as an explosive charge needing onlythe insertion of the means of initiation by the operator.

FIG. 4C shows the nozzle 38 of FIGS. 4A and B.

FIG. 5 shows a disrupter 50 of the present invention in combination withsuch other components as bring it into the scope of one of my earlierinventions, the trepanning charge (UK Patent GB 2 105 015 B) which isused to effect cutting of a disc out of a target. In this arrangement,the forward end of the consolidating ring 51 is inserted in acylindrical socket 52 on the end of a plastics cylinder 53. Within thecylinder 53 is an integral cone 54 which is attached to the distal endof the cylinder 53. It follows that the apex of the cone 54 is directedtowards the disc-shaped projectile 55.

Upon detonation of the explosive charge 56, the projectile/disc 55 ispropelled towards the cone 54 whereupon the apex of the cone 54 piercesthe disc 55 which is progressively deformed as it passes along theinside of the cylinder 53 until it is projected through the annulargroove 57 and emerges as an annulus travelling at such high velocitythat it trepans a disc from a target 58 upon which the end of thecylinder 53 abuts. This embodiment of the invention provides a means ofcutting large holes in target munitions using smaller amounts ofexplosive than are required by other explosive means. A large hole ispreferable, for example, for the rapid flooding of sea mines in order tode-activate their firing mechanisms. It will be understood that theusefulness of this charge is not limited to the practice of explosiveordnance disposal but is of general applicability in explosiveengineering.

FIG. 6 shows the shape of projectile 34, for example of two inclinedplanes terminated by the line of intersection and by a cylinder of whichthe diameter is defined by this line, otherwise an ellipse folded acrossits short axis.

In FIG. 7, disruptor 70 is shown surrounded by a plastics jacket 71which can be slid onto disruptor before the detonator is inserted. Theeffect of the water 72 which fills the jacket 71 is to confine theexplosive charge 73 and thereby increase the amount of energy impartedto the projectile 74. It will be understood that the water 72 may bereplaced by other liquids. A solution of ethylene glycol or of calciumchloride, for example, would lower its freezing point and maintain theliquid state when used at lower temperatures than the freezing point ofwater. Dissolution of such substances as calcium chloride or zincchloride as increase the density would enhance the tamping effect. Sinceany liquid in the jacket 71 is instantly dispersed as fine droplets, aliquid containing a suitable reagent could be quickly mixed with anyliquid or gaseous substances resulting from the rupturing of a targetvessel. A powerful oxidising and sterilising agent such as a solution ofcalcium hypochlorite, for example, would denature nerve gases orbio-toxins and sterilise bacterial spores.

By way of example, a charge in which the projectile was polyethylene andwater was loaded with 20 g of PE4 plastic explosive in which a 60°conical cavity was formed. The exposed surface of the explosive wassprayed with acrylic lacquer. After this had dried the remaining spacewas filled with water before insertion of a 60° polyethylene cone, 2 mmthick, apex first. The assembly thus constituted a shaped charge with apolyethylene and water conical liner. This was fired from a stand-offdistance of 50 mm at a stack of six mild steel plates each 3 mm thick.All plates were perforated. The hole diameter increased fromapproximately 8.0 mm to 10.0 mm.

In an example of the use of a water and polyethylene lined shaped chargeto disrupt a small bomb, a similar assembly was loaded with 20 g of C4plastic explosive and aimed from a stand-off distance at a point midwaybetween the driving ring and the start of the ogive of a CompositionB-filled US 51 mm mortar bomb. The fuse was ejected and the case brokeround the driving ring without apparent explosive reaction of the fill.

Another form of projectile material which evolves heat even in theoxygen-deficient interior of a munition is a heat-emitting pyrotechniccomposition. Such compositions most commonly consist of a mixture of afuel component, such a metal powder, and an oxidising salt, such as aninorganic nitrate, chlorate, perchlorate or chromate or the oxide of aheavy metal. They are therefore inherently potentially dangerous instorage and use. The present invention, which involves the violentdistortion of the projectile, thereby provides the means of mixing twoor more components which constitute separate entities in the undistortedprojectile. Thus, by way of example, a shaped charge cone might beformed in two or more layers, each of a different reagent, so thatmixing and ignition occurs only as the charge detonates and the cone isdeformed. Suitable components for such a projectile might be magnesiumand polytetrafluoroethylene. This mixture begins to react at about 493°C. with the evolution of a very large amount of heat according to theequation

Yet another consists of a compressed or encapsulated oxidant which wouldreact chemically with the oxygen deficient contents of the targetmunition. Thus TNT, which is a highly oxygen deficient explosive ofunusually low melting point but of high stability, is relativelydifficult to ignite by brief contact with even very hot metal which ittends to quench without reaction.

The explosive injection of a hot oxygen donor would constitute a morepowerful means of ignition. Though the very high proportion of oxygenin, for example, potassium perchlorate, is an attractive feature in suchan application, it has the rather high decomposition temperature ofabout 440° C. Silver nitrate and potassium permanganate, withdecomposition temperatures of 305° C. and 240° C. respectively, are thusconsiderably more powerful instigators of combustion.

In a further example of this type of charge, two similar charges wereeach loaded with 30 g of PE4 and fired simultaneously and parallel toeach other at the side of a British 81 mm mortar bomb from a stand-offdistance 50 mm. Two holes, 45 mm between centres and 12 and 6.5 mm indiameter, were made in the bomb case and the fuse was ejected withoutreaction of the explosive fill.

The use of the invention to cause the ignition of explosive-filledmunitions is illustrated by shaped charges projecting magnesium liners.

By way of example, a charge was loaded with 30 g of PE4 and a projectileconsisting of a magnesium cone with an included angle of 120° and 3 mmthick. It was aimed at the driving band of a British RDX/TNT-filledfused 81 mm mortar bomb at a stand-off distance of 50 mm. The case wassplit and the explosive and the fuse ejected without detonation.

In a further example, a similar charge was aimed from a stand-offdistance of 50 mm at the side of a plugged British 1,000 lb Mk 13 bombat a point 350 mm from the base. The bomb contained an aluminisedmixture of RDX/TNT/wax containing synthetic fibres to enhance mechanicalstrength and thus prevent cracking. The disruptor caused the bomb caseto split longitudinally and an estimated 90 per cent of the explosivefill was ejected in a single lump and projected approximately 10 metres.

In an example of firing against a large, fused, munition, a 50 g load ofC4 was used to fire a magnesium cone against the side of a US Mk 80series 500 lb aircraft bomb filled with RDX/TNT. The bomb had both anose fuse and a base fuse. It was attacked at a stand-off distance of 50mm at a point 350 mm from the base. The case split open and theexplosive fill was dispersed in mostly small pieces. Both fuses wereejected.

An example of the enhancement of target penetration by a disc affordedby an elongate nozzle is provided by a charge in which a 30 g load ofPE4 propelled a 4 mm thick magnesium disc along the lumen of an elongateplastics nozzle with an included angle of 10° and a wall thickness of 3mm. When placed normally to a thick steel plate with the apex of thecone resting upon it, a cavity 13.6 mm deep and tapering from 19 to 11mm in diameter was formed.

An example of the highly directive qualities of an elongate cone isprovided by a charge loaded with 10 g of C4 propelling a composite coneof polyethylene and water along the inside of a similar elongateplastics cone. This was directed at the capacitor of a fast acting highvoltage firing circuit connected to a remote electric fuse bead. Thecircuitry included a switch consisting of a metal foil and papersandwich which was penetrated as the disrupter was actuated. Thisinitiating circuit, and two plastics containers of water, having a wallthickness of less than one millimetre, were contained within a cardboardbox. Firing of the disruptor generated a jet of polyethylene and waterwhich travelled at such velocity as to penetrate and discharge thecapacitor before the remote fuse head had time to explode.

Despite some tearing of the cardboard box, the plastics containers ofwater were not ruptured.

A further example of the usefulness of the nozzle is illustrated by thefiring of a similar charge to that used in the preceding example againstthe anti-lift fuse of a limpet mine attached to a steel plate underwater. The mine was removed from the steel plate and the switchimmobilised in such a manner as would have prevented the initiation ofthe mine.

The following example illustrates the functioning of the embodiment ofthe invention used for the purpose of trepanning. A charge was loadedwith 30 g of PE4 and a projectile consisting of a disc of aluminium 2.8mm thick and weighing 5.5 g. The charge was fitted to an ABS plastictrepanning attachment containing a 25° cone, the base of which restedupon a sheet of mild steel 6 mm thick. Upon detonation, the charge cut aneat hole 38 mm in diameter. A steel disc 26 mm in diameter wasrecovered.

Yet another example illustrates the applicability of the invention tothe attack of munitions or other targets at large stand-off distances. Acharge was loaded with 50 g of PE4 and a projectile consisting of a 150°copper cone 1.64 mm thick with a rounded apex. At a stand-off distanceof 1400 mm it produced a very neat hole 17 mm in diameter through a 10mm thick mild steel plate.

In FIG. 1 to 3, the tubular element to the left of ridge 10 mimics thecorresponding end of one of other existing devices, the Jet. Theimportance of the shape is that it enable one to fit various componentsoriginally developed for the Jet onto a disrupter of the presentinvention. The square shoulder at its distal extremity is to accommodatean O-ring which seals the joint when the elongate nozzle 21 is attachedfor use under water. Another example of such fittings is the trepanningattachment 27.

Special features enabling the kit of parts to be assembled intodifferent forms of disruptor include the following:

1. The consolidating ring (for example 8) is threaded internally so thatit engages with the thread on the outside of the body 1. This enablesthe operator to press any of a variety of projectiles against theexplosive within the body by screwing the consolidating ring onto thebody until tight. It then holds the projectile in that position. Thisobviates the need of cement which has previously been necessary for sucha purpose but which is inconvenient to use in the field.

2. The spacer (for example 12) provides a means of translating thepressure applied by the tightened consolidating ring 8 against whateverprojectile is being used. Its use enables the operator to assemble avariety of charges with a variety of projectile thickness and with arange of explosive loads.

3. The projectile (for example 7) represents a cone made of magnesiumwhich is employed when an incendiary effect on the target is required.It is thicker than a conventional shaped charge liner of such a diametersince the density of magnesium (1.7 g/cm³) is much lower than that ofmetals more commonly used such as copper (8.95 g/cm³). The nature of theprojectile material and the shape enables the operator to assemblecharges with a particular terminal effect on a target. This may be theignition of an explosive or pyrotechnic fill by means of the lowdensity, fiercely combustible magnesium, or the detonation of anexplosive-filled target or the penetration of thick metal by means of aconical liner of a high density, non-igniferous metal as copper ortantalum. A projectile consisting of water and polyethylene, in whichthe polyethylene cone 15 serves principally to give shape to the water,constitutes a shaped charge with a liner of quite unusually low densityand high thermal conductivity and is able to penetrate steel cases, toimpinge upon explosives without causing their detonation or ignition,and to burst open target munitions or eject their fuses and thus renderthem safe. The relatively acute angle of the polyethylene cone 15, andof the cavity in the explosive 14, compared with that of the magnesiumcone 7 is employed in order to enhance the penetration of the lowdensity polyethylene and water composite projectile.

4. The purpose of the film of lacquer applied to the surface of theexplosive 11 is to protect the explosive from the action of water. Thisis less important in the case of highly water resistant explosives, suchas those which incorporate mineral oil in their composition, but it isadvantageous in the case of explosives such as PE4 plastic explosivewhich contain hydrophyllic components in their composition and in thecase of explosives which are soft and likely to undergo deformation ifhandled roughly. A more robust alternative to lacquer is a plasticsformer, for example in the shape of a cone or a diaphragm. Lacquer hasthe advantage, however, of conforming with any shape which might beimparted to the surface of the explosive.

FIG. 9 shows another disrupter 100 which corresponds to the simplest ofthe variants described hereinabove, and having no nozzle, but with threewire legs 101, 102, and 103 spread equally to provide a secure support.

Three simple tools may be advantageously employed for loading chargesmade according to the invention.

Of these the first is a volumetric measure consisting of a plasticstube, the outside of which bears circumferential grooves on the outsideto provide a firm grip. In the wider of the two grips shown, a letteredpiece of polyethylenic heat-shrink tubing is collapsed. This istransparent and printed with the approximate explosive load which themeasure contains when completely filled. By printing with mirror-imagelettering and everting before shrinking it into position, the letteringmay at once be read through the translucent plastic sleeve and beprotected from abrasion by it.

The body of the measure may advantageously be made frompolytetrafluoroethylene (PTFE) since explosive substances tend to stickless to it than to other plastics.

The measure is filled by pushing the angled end into a mass of plasticexplosive on a clean work surface. When explosive extrudes from thesquare end, any excess may be removed by stroking with the stemming rod.

The wide end of the same stemming rod is then used to expel theexplosive from the lumen of the volumetric measure in the form of aregular slug. The volumetric measure may conveniently have suchdimensions as yield a slug of 20 g. This simple means enables theoperator easily to prepare aliquots of explosive which are accurate towithin less than 3%.

This combination of tools offers great ease of use in diverse workingconditions, is simple to learn to use, applicable to all malleableplastic explosives and very inexpensive compared with the simplest ofbalances. Unlike a balance, it may readily be used aboard a ship.

The stemming rod is provided with one end which is narrower than theother. This facilitates the tamping of plastic explosive against the endof the dummy detonator. The wider end serves to consolidate theexplosive in the rest of the case.

It is the purpose of the mandrel to provide the exposed surface of theexplosive with a shape appropriate to the projectile about to be loaded.To this end, it has one square end and one with a 60° point.

The invention may usefully be used for the rendering safe of limpetmines attached to the sides of ships or other underwater structures.Once the presence of such a mine is recognised or suspected, the soonerthe response the more likely it is to be successful. Time can be savedby loading the charge with explosive but no water. By providing the bodywith a series of holes round its periphery, water may be allowed toflood in within approximately one second after immersion in water. Thisarrangement allows the charges to be stored dry and so free of risk ofwater loss through leakage and free of the risk of freezing anddistortion if subjected to a cold environment.

Referring to FIG. 10, there is shown a disruptor 130 for underwater use.Explosive 131 is loaded into the body 132 and the shape of its forwardedge, which may be flat or provided with concavity is maintained by theflat or concave plastic diaphragm 133 which is provided with an integralspigot 134. This spigot 134 bears at least one hole 135 which is largeenough to assure that a ring of holes 136 in the body will to asubstantial extent be aligned with the holes 135. Thus, regardless ofthe rotational position of the diaphragm/spigot component 133 & 134,sufficient leakage path for surrounding water will occur to ensure thatthe cavity 137 forward of the diaphragm/spigot component 133 & 134 willbe quickly flooded upon immersion.

The forward end of the cavity 137 is conveniently defined by athin-walled plastics cone 138 which is integral with the threadedconsolidating ring 139. This arrangement also ensures that the stand-offspace 140 is maintained free of water.

In this embodiment, which is designed specifically for underwater use,the main component of the projectile is water 137, the forward edge ofwhich is defined by a thin plastics cone 138 which is rigidly attachedto, or integral with, either the body 132 or the consolidating ring 139.The volume of the water-filled cavity is therefore fixed. It is theconically formed surface of the explosive 131, or a thin plastics conedefining its forward surface which defines the rear surface of the watercomponent of the projectile. The size of explosive materials enclosureis determined by the consolidating ring 139 and/or body 132.

The arrangement of FIG. 10 is particularly suited to underwaterapplications in that disruptor 130 can be manufactured and stored withcavity 137 empty, which is only filled with water once disruptor is putinto position for use, whereupon water enters cavity 136 within 2 or 3seconds of complete immersion in water.

In order to facilitate the use of the invention underwater, theopen-ended threaded consolidating ring may be provided with an integralwaterproof capsule which prevents the ingress of water into thestand-off space between the projectile and the target surface. Thoughthe thread of the capsule can be waterproofed by the use of cement, PTFEtape or adhesive plastic tape, another means of sealing the assemblyagainst the ingress of water is a rubber or plastic sleeve which isapplied to the outside of the body. Such a sleeve may consist of rubberor of heat-shrinkable plastic.

The elasticity of a thin rubber sleeve is advantageous for applicationin the field although polyolefinic heat shrinking tubing with a meltablelining may be convenient when a means of applying heat is alsoavailable.

By way of example, a charge was loaded with 40 g of plastic explosive C4and a magnesium cone and provided with a capsule which determined astand-off space of 80 mm. It was fired against a 5 inch US fused shellfilled with ammonium picrate (Explosive D) underwater at a depth ofsixteen metres. The shell had lain on the sea-bed for several decades.The point of aim was approximately half way along the shell. The shellwas penetrated and burst open as a result of low order reaction of itsfill. This result dispels the commonly-held belief that such munitionscannot be low-ordered underwater and is significant as far as protectionof marine fauna is concerned.

In a further example, a charge was loaded with 45 g of plastic explosiveC4 and a copper cone. The charge was aimed along the long axis of asimilar shell and pointed at the base fuse. The shell detonated.

In an example of the use of the disrupter in air, a charge was loadedwith 20 g of plastic explosive PE4 and a magnesium cone and aimed from adistance of 50 mm at the side a steel-cased, TNT-filled Mk7/7 anti-tankmine in the open. The charge was thus aimed directly at the central fuzeassembly. The shot resulted in the penetration of the case, blowing offthe crimped steel cover of the mine and scattering the shatteredexplosive fill. Local soot deposition and a bulge round the entry holeindicated the participation of a very small proportion of the explosivefill in the event. No damage was caused to the fuze well, indicatingthat the reacting TNT had stopped further advance of the magnesium jetand thus protected the relatively sensitive fuze and booster fromattack. This result is significant in that it dispels the commonly heldbelief that TNT-filled munitions cannot be low-ordered by explosiveattack.

1. A single-use disruptor including an explosive charge, the disruptorcomprising a container for a projectile and explosive material, thedisruptor and container for destruction in its single-use afterdetonation of the explosive material, the container comprising: anenclosure for holding explosive material, said enclosure having a wallof the projectile locatable at any one of a number of positions definingthe capacity of said enclosure for explosive material, and one or morespacer elements to hold the wall in one position and so define theenclosure, wherein the one or more of the spacer elements are providedin the container but outside the enclosure.
 2. A single-use disruptoraccording to claim 1 wherein one or more of the spacer elements areprovided in the enclosure.
 3. A single-use disruptor including anexplosive charge, the disruptor comprising a container for a projectileand explosive material, the disruptor and container for destruction inits single-use after detonation of the explosive material, the containercomprising: an enclosure for holding explosive material, said enclosurehaving a wall of the projectile locatable at any one of a number ofpositions defining the capacity of said enclosure for explosivematerial, and one or more spacer elements of annular form to hold thewall in one position and so define the enclosure.
 4. A single-usedisruptor including an explosive charge, the disruptor comprising acontainer for a projectile and explosive material, the disruptor andcontainer for destruction in its single-use after detonation of theexplosive material, the container comprising: an enclosure for holdingexplosive material, said enclosure having a wall of the projectilelocatable at any one of a number of positions defining the capacity ofsaid enclosure for explosive material; and one or more spacer elementsto hold the wall in one position and so define the enclosure, wherein atleast one of the one or more spacer elements comprises a hollowcompartment for water or other filler material.
 5. A single-usedisruptor according to claim 1 wherein the projectile further comprisesthe one or more spacer elements.
 6. A single-use disruptor according toclaim 1 wherein the projectile is of one of the following shapes: (i) acone form; (ii) a flat disc; (iii) a radially symmetric body providedwith a spherical, hyperbolic or other concavity; (iv) a wedge ofV-shaped section.
 7. A single-use disruptor according to claim 1 whereinthe projectile is made of one of the following materials: (i) magnesium;(ii) zirconium; (iii) titanium.
 8. A kit of parts for a disruptoraccording to claim 1, the kit of parts including a container for adisruptor, a projectile, an enclosure for holding explosive materialhaving a wall of the projectile locatable at anyone of a number ofpositions thereby to define the capacity of said enclosure.
 9. Asingle-use disruptor according to claim 1, wherein the enclosurecomprises a detonator disposed in said enclosure for detonating saiddisruptor.
 10. A single-use disruptor including an explosive charge, thedisruptor comprising a container for a projectile and explosivematerial, the disruptor and container for destruction in its single-useafter detonation of the explosive material, the container comprising: anenclosure for holding explosive material, said enclosure having a wallof the projectile locatable at any one of a number of positions definingthe capacity of said enclosure for explosive material; and aconsolidating ring that engages with a first end of the container; anexplosive material disposed in the container; and a projectilepositioned in the container by the consolidating ring at any one of anynumber of positions to form an enclosure for the explosive material,wherein the projectile is axially aligned with an axis of the containerby the consolidating ring and wherein a wall of the projectile is urgedagainst the explosive material.
 11. The single-use disruptor of claim10, further comprising one or more spacer elements to hold the wall in aparticular position.
 12. The single-use disruptor of claim 10, furthercomprising a nozzle connected to the consolidating ring, wherein thenozzle collimates the projectile.
 13. The single-use disruptor of claim10, further comprising water positioned between the projectile and theexplosive material.